Stabilization of synergistically sensitized photographic systems



United States Patent 3,297,447 STABILIZATION OF SYNERGISTICALLY SENSI-TIZED PHOTOGRAPHIC SYSTEMS Patricia A. McVeigh, Rochester, N.Y.,assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of NewJersey N Drawing. Filed Sept. 9, 1965, Ser. No. 486,235 22 Claims. (Cl.96-109) This application is a continuationdn-part application of mycopending application Serial No. 384,528, filed July 22, 1964, nowabandoned. V

This invention relates to photography and more particularly to thestabilization of photographic systems sensitized with a combination of anoble metal sensitizer, e.g., a gold salt, and a labile seleniumsensitizer.

It is known that photographic systems such as silver halide systems,particularly gelatino silver halide emulsions, can be sensitizedchemically with a combination of a noble metal sensitizer, e.g. a goldsalt, and a labile sulfur compound. It is, furthermore, known thatphotographic silver halide emulsions can be sensitized with labileselenium compounds. It has been generally thought that he sensitizationof such emulsions by means of labile selenium requires a somewhat largeramount of sensitizer than when a sulfur sensitizer is employed.

In copending applications Serial No. 343,456, filed February 10, 1964,now abandoned, and Serial No. 468,972, filed July 1, 1965, of Joseph S.Dunn, it is shown that small amounts of selenium sensitizers can beemployed in combination with noble metal sensitizers to produce effectswhich cannotbe obtained with a combination of sulfur sensitizer andnoble metal sensitizer, even where a considerably larger amount ofsulfur sensitizer than selenium sensitizer is employed. Since the priorart tends to treat selenium and sulfur sensitizers as equivalents, thisbehavior was not anticipated.

While the Dunn photographic systems referred to above do produce markedincreases in speed, as compared with gold-and sulfur-sensitizerphotographic systems, they introduce a problem of stability, which canbe an important factor in some instances.

It is, therefore, an object of my invention to provide new stabilizedphotographic systems sensitized with a combination of a labile seleniumsensitizer and a noble metal sensitizer for increasing the speedsynergistically of such photographic systems. It is another object ofthis invention to provide new stabilized synergistically sensitizedsilver halide emulsions without adversely affecting the speed of suchemulsions. Other objects will become apparent from a consideration ofthe following description and examples.

I have now found that photographic systems sensitized with a combinationof a noble metal and labile selenium can be effectively stabilized byincluding in the photographic system a labile sulfur compound. In myinvention, these labile sulfur compounds do not cause any phenomenalincrease in the speed of the emulsions but they do cause a verysignificant increase in the stability of such sensitized photographicsystems. While the invention described in the aforementioned Dunnapplications is outstanding in providing marked increases in speed, ascompared with known methods of chemical sensitization, the method ofDunn sometimes leads to an increase in fog. While there are certainmeans described by Dunn for controlling fog, I have found that thelabile sulfur compounds of my invention provide a particularlyefficacious means of controlling fog without deleteriously affecting thespeed of the stabilized photographic system. In some instances there mayalso be a small increase in speed as a consequence of the addition ofthe labile sulfur compound.

Particularly useful labile sulfur compounds for my invention include thewell-known class of compounds which have been previously identified aslabile sulfur sensitizers. These include the water-soluble thiosulfa-tessuch as alkali metal thiosulfates including sodium and potassiumthiosulfates, as well as ammonium thiosulfate; thioureas such asthiourea, allylisothiourea, diacetylthiourea; thiosemicarbazide;thiocarbamates such as isopropylthiocarbamate; and the like labilesulfur compounds. Other labile sulfur compounds useful in my inventionare described in an article by T. H. James and W. Vanselow in J. Phot.Sci., vol. 1 (1953), page 133, as well as in an article by A Hautot andH. Sauvenier in Sci. Ind. Phot., vol. 27 (1957), No.1.

The amount of labile sulfur compound used in my invention can varyconsiderably depending upon the particular sensitized photographicsystem employed, finishing conditions, including temperature and time ofdigestion and ripening, etc. In general, I have found that the uniquestabilizing effect of labile sulfur compounds can be accomplished at asomewhat lower concentration than might be required in their use assulfur sensitizers. With reference to silver halide photographicsystems, particularlyuseful results have been obtained at concentrationsof about 0.1 to 10 mg. per mole of silver halide. Larger or smallerquantities can be employed without adversely affecting the sensitometricproperties of the photographic system. The labile sulfur compounds areefficaciously added to be present during the chemical sensitization ofthe photographic system.

The selenium sensitizers useful in my invention include a wide varietyof labile selenium sensitizers, many having been previously suggestedfor use alone in sensitizing photographic silver halide emulsions.Suitable selenium addenda are disclosed in Sheppard et al. US. Patent1,623,- 499, issued April 5, 1927, .as well as Sheppard US. Patents1,574,944, issued March 2, 1926, and 1,602,592, issued October 12, 1926.The labile selenium sensitizers of my invention which have been found tobe particularly useful are organic selenium compounds wherein theselenium atom is doubly bonded to a carbon atom of the organic compoundthrough a covalent linkage. Thus, especially useful compounds includeselenoamides, selenoketones (especially ketones having an alkyl radicalattached to the L J=Se l moiety), selenocarboxylic acids and esters,etc. Useful groups of selenium sensitizers include aliphatic selenoureaswherein the aliphatic radical is, for example, an alkyl radical such asmethyl, ethyl, propyl, isopropyl, butyl, heXyl, octyl, etc. Suchselenoureas have at least one hydrogen atom attached to the nitrogenatom thereof, thus making possible the formation of an enol tautomer.Also useful in my invention are analogous selenoureas containing one ormore aromatic radicals, such as phenyl, tolyl, etc., or heterocyclicradicals, such as benzothiazolyl,

syridyl, etc., and aliphatic isoselenocyanates. Other useful labileselenium sensitizers are selenophosphates such as tri-alkyl and tri-arylselenophosphates. It has also been found that colloidal selenium itselfis a useful sensitizer.

Illustrative addenda suitable for furnishing the labile selenium moietyin the stabilized photographic systems of the invention include:

colloidal selenium, selenoacetone, selenoacetophenone,tetramethylselenourea,

N- (fi-carboxyethyl) -N,N'-dimethylselenourea, selenoacetamide,diethylselenide, triphenylphosphine selenide,tri-p-tolylselenophosphate, tri-n-butylselenophosphate, 2-selenoproponicacid, 3-selenobutyric acid, methyl-3-selenobutyrate, allylisoselenocyanate, and dioctylselenourea.

The concentration of selenium sensitizer can be varied considerablydepending upon the particular selenium addendum employed (somesensitizers being more efficacious than others), the nature of thephotographic system, the amount and chemical nature of the noble metalsensitizer, etc. In silver halide systems, for example, I have foundthat useful results can be obtained using amounts as small as 0.05 mg.of selenum sensitizer per mole of silver halide although considerablylarger amounts can also be employed, such as 5.0 mg. or more per mole ofsilver halide.

The term labile as used herein has the meaning well understood by thoseskilled in the art of photography, i.e., a material which yields asilver salenide or sulfide that is insoluble in water at roomtemperature (20 C.) upon addition to an aqueous silver nitrate solution.For example, selenourea is a labile selenium compound, since silverselenide precipitates when selenourea is added to an aqueous silvernitrate solution. Similarly, colloidal selenium precipitates silverselenide upon addition to aqueous silver nitrate and is, therefore, alabile selenium addendum or sensi-tizer of invention. Likewise, sodiumthiosulfate is a labile sulfur compound as silver sulfide precipitateswhen an aqueous sodium thiosulfate solution is added to an aqueoussilver nitrate solution.

The noble metal sensitizers useful in the photographic systemsstabilized in accordance with my invention include the well-known goldsensitizers which have been previously recognized as useful in thephotographic art and found to be outstanding intheir sensitizing action,including water-soluble and water-insoluble organic and inorganic goldcompounds and salts, although other noble metal sensitizers can be used,including palladium, platinum, etc., sensitizers such as are disclosedin Smith et al., U.S. Patent 2,448,060, issued August 31, 1948. Typicalsuitable gold sensitizers are described in Waller et al., U.S. Patent2,399,083, issued April 23, 1946, and Damschroder et al., U.S. Patent2,642,361, issued June 16, 1953.

Illustrative addenda suitable for furnishing the noble metal moiety inthe sensitizer combinations of the invention include:

gold chloride,

potassium aurate,

potassium auriaurite,

potassium auricyanide,

potassium aurithiocyanate,

gold sulfide,

gold selenide,

gold iodide,

potassium chloroaurate, ethylenediamine-bis-gold chloride,

4 ammonium chloroplatinite, i.e., (NH PtCl ammonium chloropalladate,i.e., (NI-I PdCl and organic gold sensitizers having the formulas:

CH: C

II. S\

I C-SAu N N C2 H5 C1 III. 0

N zHa C=GHCH=G (LL s Au i S P3 O1 N om. C=C y: SM N S 12115 CCH3 C2115AllCl;

VI. S H H2 CCH=CHN OH: (I C N\ Hz H2 Cfia AuCl; VII. f

@ N O $2115 (lg H5 AuCh VIII. S i S\ C=CH-C N N i 'zHa C2 Ha U C=CH 1\N/ N CzH A1101: $2155 AuCh X. s s

/ I C=CHC I 2 5 C2115 The quantity of noble metal sensitizer useful insensitizing the photographic systems of the invention can likewise bevaried as in the case of selenium sensitizer. I have found, for example,that amounts varying from about 0.1 to 5.0 mg. of gold sensitizer permole of silver halide are quite satisfactory.

The noble metal moiety and the labile selenium moiety used insensitizing the photographic systems stabilized in accordance with theinvention are more generally added to the photographic system asseparate entities, although such is not necessary.

It has been found that particularly useful results are obtained inprepared noble metal and selenium sensitizing combinations in caseswhere as water-soluble thiocyanate compound is present. Typicalthiocyanates include sodium thiocyanate, potassium thiocyanate, ammoniumthiocyanate, etc. Other water-soluble thiocyanates can be employed toequal advantage. The amount of thiocyanate compound used can likewise bevaried, depending upon the particular system being sensitized, relativeamounts of selenium and noble metal sensitizers,

etc.

The sensitizing addenda used in sensitizing the photographic systemsstabilized in accordance with the invention can be added in a variety ofways to photographic systems and at various stages in the preparation ofsuch. In general, with respect to silver halide emulsions, such addendacan be added with useful effects at the completion of the Ostwaldripening and prior to one or more of the final digestion operations. Thesensitizing addenda of the invention are preferably added to silverhalide emulsions after the silver halide grains are substantially intheir final size and shape. The addenda can be added in the form oftheir aqueous solutions, Where they are soluble in water, or in aninnocuous organic solvent where the sensitizer does not have suflicientsolubility in water to be used in the form of an aqueous solution.Particulanly useful organic solvents include ethanol, methanol,pyridine, acetone, dioxane, etc. That is, organic solvents which have arather high degree of polarity are preferred. Where it is desired to addthe sensitizing addenda in some other form than a solution, thisprocedure is also possible, especially where the sensitizer is availablein the form of a colloidal suspension. In some cases, it is possible toadd the sensitizers suspended in an organic solvent which forms verysmall suspended particles or globules in the photographic emulsionsimilar to the type of colloidal particle produced in preparing couplerdispersions. Dispersing media useful for this purpose include tricresylphosphate, dibutyl phthalate, triphenyl phosphate, etc. The order ofaddition of sensitizers and stabilizers to the emulsion can be varied.For example, the sensitizers (part or all) can be added before or afterthe sulfur stabilizer. Especially useful results are obtained where alladdenda are added prior to the final digestion.

In the preparation of dispersions of light-sensitive materials such assilver halide and the like, there can be employed as the dispersingagent gelatin or some other colloidal material, such as colloidalalbumin, a cellulose derivative or a synthetic resin, for instance, apolyvinyl compound. Hydrophilic colloids which can be used are polyvinylalcohol or a hydrolyzed polyvinyl acetate as described in Lowe U.S.Patent 2,286,215, issued June 16, 1942; a far hydrolyzed cellulose estersuch as cellulose acetate hydrolyzed to an acetyl content of 19 to 26%as described in U.S. Patent 2,327,808, of Lowe and Clark,

issued August 24, 1943; a water-soluble ethanolamine cellulose acetateas described in Yutzy U.S. Patent 2,322,- 085, issued June 15, 1943; apolyacrylamide or an imidized polyacrylamide as described in Lowe, Minskand Kenyon U.S. Patent 2,541,474, issued February 13, 1951; copolymers(alone or in admixture with another colloid, e.g., gelatin) of an alkylacrylate, e.g., ethyl or butyl acrylate, and acrylic acid, such as thosedescribed in Houck et al. U.S. Patent 3,062,674 issued November 6, 1962and Houck et al. U.S. application Serial No. 139,- 313, filed September19, 1961; zein as described in Lowe U.S. Patent 2,563,791, issued August7, 1951; a vinyl alcohol polymer containing urethane carboxylic acidgroups of the type described in Unruh and Smith U.S. Patent 2,768,154,issued October 23, 1956; or containing cyanoacetyl groups such as thevinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh, Smithand Priest U.S. Patent 2,808,331, issued October 1, 1957; or a polymericmaterial which results from polymerizing a protein or a saturatedacylated protein with a monomer having a vinyl group as described inU.S. Patent 2,852,- 382, of Illingsworth, Dann and Gates, iissuedSeptember 16, 1958. Mixtures of such dispersing agents in a wide rangeof proportions can be utilized, typical of such mixtures being mixturesof gelatin and an acrylate-acrylic acid copolymer.

The loss of density sometimes occurring when a photographic emulsion isdried can be prevented or substantially reduced by incorporating in thegelatin silver halide emulsions of my invention a water-soluble,gelatin-compatible vinyl monomer. Only a small amount of such anaddendum is generally required, and frequently amounts as small as about5%, based on total solids in the emulsion are useful, although it isobvious that much larger amounts, such as about can be employed incertain types of emulsions. Typical polymers which can be used incombination with gelatin to prevent loss of density and thereby increasethe covering power in the processed, dried layer include the polyvinyllactams, such as polyvinylpyrrolidone, as well as other polyvinyllactams described in Du Pont British Patent 867,899, published May 10,1961. Other useful polymers include polyacrylamide types, such aspolyacrylamide itself, or copolymers of acrylic amide with otherethylenically-unsaturated monomers, including acrylic acid, methacrylicacid, methacylamide, acrylonitrile, methyl acrylate, butyl acrylate,methyl methacrylate, butyl methacrylate, or mixtures of these monomers.Other colloids useful in preventing or inhibiting such density lossesinclude natural gums, salicylic acid condensates, etc.

I have found that the speed of noble metal-selenium sensitized emulsionsstabilized with a labile sulfur compound can be further increased byincluding in the emulsions a variety of hydrophilic colloids, such ascarboxymethyl .protein of the type described in U.S. Patent 3,011,- 890,issued December 5, 1961. Polysaccharides of the type described inCanadian Patent 635,206 can also be used to further increase the speedof my emulsions.

Such emulsions can contain speed-increasing compounds of the quaternaryammonium type of CarrollU.S. Patent 2,271,623, issued February 3, 1942;Carroll and Allen U.S. Patent 2,288,226, issued June 30, 1942; andCarroll and Spence U.S. Patent 2,334,864, issued November 23, 1943; orthe polyethylene glycol type of Carroll and Beach U.S. Patent 2,708,162,issued May 10, 1955; or the quaternary ammonium salts and polyethyleneglycols of Piper U.S. Patent 2,886,437, issued May 12, 1959; as well asthe thiopolymers of Graham and Sagal U.S. Patent 3,046,129, issued July24, 1962, and the Dann and Chechak U.S. Patent 3,046,134, issued July24, 1962. Prequently, useful effects can be obtained by adding theaforementioned speed-increasing compounds to the photographic developersolutions instead of, or in addition to, the photographic emulsions.

The photographic systems stabilized according to the technique of myinvention are especially useful in the preparation of integral screenX-ray materials. Such X-ray materials have the advantage of convenienceof handling and improved sharpness, inasmuch as they can be preparedusing a single silver halide emulsion coated on but one side of thephotographic support, as compared with conventional X-ray materialswhich have a silver halide emulsion layer coated on each side of thesupport (i.e., duplitized material). Since an opaque screen is employedin integral X-ray materials, the possibility of using an emulsion ononly one side of the support is most desirable, and by using the novelemulsions of my invention, it is possible to use silver halide emulsionhaving finer grain to reach a given speed. This results in highercontrast for such a material, since finer grain emulsions inherentlyproduce higher contrast. Thus, for the same grain size, it is possibleto obtain higher speeds with the selenium-gold sensitized emulsions ofmy invention. An integral screen X-ray material using the novelemulsions of my invention can have the layer arrangement shown in FrenchPatent 1,324,023, issued March 4, 1963. In such an arrangement theintensifying screen is located on the side opposite to the emulsion sothat the screen remains with the positive after stripping. Otherarrangements which can be used in the preparation of integral screenmaterials are described in Blake et al. US. Patent 2,887,379, issued May19, 1959 (col. 8, lines 4 to 21). In a typical integral screen X-raymaterial of my invention, a conventional support is coated in successionwith an intensifying screen, receiving layer, silver halide emulsionlayer containing my novel combination of selenium and noble metalsensitizers, and if desired, a thin protective layer of gelatin (whichcan be omitted, if desired). Other arrangements will become apparent tothose skilled in the art.

In addition to being useful in X-ray and other nonoptically sensitizedsystems, the stabilized photographic systems of the invention can alsobe used in orthochromatic, panchromatic, and infrared sensitive systems.Various silver salts can be used as the sensitive salt in sensitizedsilver halide systems stabilized in accordance with the invention suchas silver bromide, silver iodide, silver chloride, or mixed silverhalides, such as silver chlorobromide or silver bromoiodide. The presentphotographic systems can be used for color photography, for example, insilver halide emulsions containing color-forming couplers or emulsionsto be developed by solutions containing couplers or othercolor-generating materials, emulsions of the mixed-packet type, such asdescribed in Godowsky US. Patent 2,698,794, issued January 4, 1955; insilver dye-bleach systems; and emulsions of the mixedgrain type, such asdescribed in Carroll and Hanson US. Patent 2,592,243, issued April 8,1952.

Typical color-forming compounds or couplers which are useful in colorphotography, according to our invention, include the following:

COUPLERS PRODUCING CYAN IMAGES 5-(p-amylphenoxybenzenesulfonamino)-1-naphthol 5 (N-benzyl-N-naphthalenesulfonamino) -1 -naphtho15-(n-benzyl-N-n-valerylamino) -1-naphthol S-caproylamino-1-naphthol2-chloro-5- (N-n-valeryl-N-p-isoproylbenzylamino1-naphthol-2-carboXylic-a-naphthalide 1-naphthol-5-sulfo-cyclohexylamide5 -phenoxyacetaminol-naphthol S-B-phenylpropionylaminol-naphtholMonochlor-5- (N-y-phenylpropyl-N-p-sec.-amylbenzoylamino)-l-naphtholZ-acetylamino-5-methylphenol .2-benzoylamino-3,S-dimethylphenol Z-oz(p-tert. amylphenoxy) n-butyrylamino-S-methylphenol 6 {v-{4- ['y-2,4-di-tert. amylphenoxy butyramido] phenoxy} acetamido}-2,4-dichloro-3-methylphenol l-hydroxy-Z- 5- 2,4-di-tert. amylphenoxy) -n-butyl]naphthamide Z-cc (p-tert. amylphenoxy) -n-butyrylamino-4-chloro-S-methylphenol 2- p-tert. amylphenoxy-p-benzoyl) amino-4-chloro-S-methylphenol 2- 4-tert. amyl-3 -phenoxybenzoylamino-3,5-dimethyll-phenol 2-phenylacetylamino-4-chloro-S-methylphenol2-benzoylamino-4-chloro-5-methylphenol2-anilinoacetylamino-4-chloro-5-methylphenol 2-{4'- [a- 4-tert.amylphenoxy -n-butyrylamino] benzoylamino}-4-chloro-5-methylphenol 2-4-,3 (4-tert. amylphenoxy benzoylamino] benzoylamino-4-chloro-5-methylphenol 2-p-nitrobenzoylamino-4-chloro-5-methylphenol2-m-aminobenzoyl-4-ch1oro-5-methylphenol 2-acetarnino-4-chloro-5-metl1ylphenol 2 (4-sec. amylbenzamino) -4-chloro-5-methylphenol 2(4-n-amyloxybenzamino -4-chloro-5-methylphenol 2 (4-phenoxybenzoylaminophenol 2 (4"-tert. amyl-3 '-phenoxybenzoylamino phenol 2- oz- (4-tert.butylphenoxy) propionylamino] phenol 2- u- (4'-tert. amylphenoxypropionylamino] phenol 2- [N-methyl-N- (4"-tert. amyl-3phenoxybenzoylamino) phenol 2- (4"-tert. amyl-3 '-phenoxybenzoylamino-3-methyll-phenol 2- (4"-tert. amyl-3 '-phenoxybenzoylamino-6-methyll-phenol 2- 4"-tert. amyl-3 '-phenoxybenzoylamino-3,6-dimethylphenol 2,6-di (4-tert. amyl-3 '-phenoxybenzoylaminol-phenol Z-oc- (4'-tert. amylphenoxy) butyrylaminol-phenol 2 (4-tert.amyl-3 -phenoxybenzoylamino -3,5-dimethyll-phenol 2- a- (4'-tert.amylphenoxy -n-butyrylamino] -5-methy1- l-phenol 2 (4-tert. amyl-3'-phenoxybenzoylamino -4-cl1lorol-phenol 3- a- (4-tert. amylphenoxy-n-butylrylamino] -6-chlorophenol 3- (4-tert. amyl-3-phenoxybenzoylamino phenol 2- oz- (4-tert. amylphenoxy)-n-butyrylan1ino] -6-chlorophenol 3- Ot- (4'-tert. amylphenoxy-n-butyrylamino] -4-chlorophenol 3 06- (4-tert. amylphenoxy-n-butyrylamino] -5-chlorophenol 3 a- (4-tert. amylphenoxy)-n-butyrylamino] -2-chlorophenol Z-nc- (4-tert. amylphenoxybutyrylamino)-5-chlorophenol 2- (4"-tert. amyl-3 '-phenoxybenzoylamino-3-chlorophenol 5-benzene sulfonamino-l-naphthol2,4-dichloro-5-benzenesulfonaminol-naphthol 2,4-dichloro-5-(p-toluenesulfonamino -l -naphthol5-(1,2,3,4-tetrahydronaphthalene-6-sulfamino-1-naphthol 2,4-dichloro-5-(4'-bromodiphenyl-4-sulfon amino l-naphthol 5 quinoline-S -sulfamino-1-naphthol Any of the acylaminophenol couplers disclosed in Salminenand Weissberger US. Patent 2,423,730, dated July 8, 1947, can be used ascouplers for the cyan image,

etc.

COUPLERS PRODUCING MAGENTA IMAGES l-p-sec.amylphenyl-3-n-amyl-5-pyrazolone 2-cyanoacetyl-5- (p-sec.amylbenzoylamino) coumarone 2-cyanoacetylcoumarone-5- (n-amyl-p-sec.amylsulfanilide) Z-cyanoacetylcoumarone-S- (N-n-amyl-p-tert.amylsulfanilide) 2-cyanoacetylcoumarone-5-sulfon-N-n-buty1anilideZ-cyanoacetyl-S-benzoylamino-coumaroneZ-cyanoacetylcoumarone--sulfondimethylamideZ-cyanoacetylcoumarone-S-sulfon-N-methylanilide Z-cyanoacetylnaphthalenesulfon-N-methylanilide 2-cyanoacetylcoumarone-5- (N'y-phenylproyl-p-tert.

amylsulfonanilide l-p-laurylphenyl-3 -methyl-5-pyrazolone 1-B-naphthyl-3-amyl-5-pyrazolone l-p-nitrophenyl-3-n-amyl-5-pyrazolone1-p-phenoxyphenyl-3-n-amyl 5-pyrazolone 1-phenyl-3 -n-amyl-5-pyrazolone1,4-phenylene bis-3-( l-phenyl-S-pyrazolone)1-phenyl-3-acety1amino-S-pyrazolone1-phenyl-3-propionylamino-S-pyrazolone1-phenyl-3-n-valerylamino-S-pyrazolonel-phenyl-3-chloroacetylamino-S-pyrazolone1-phenyl-3-dichloroacetylamino-5-pyrazolone1-phenyl-3-benzoylamino-S-pyrazolone 1-phenyl-3- (m-aminobenzoyl)amino-S-pyrazolone 1-phenyl-3- (p-sec. amylbenzoylamino -5-pyrazolonel-phenyl-3-diamylbenzoylamino-5-pyrazolone1-phenyl-3-fi-naphthoylamino-S-pyrazolone 1-phenyl-3 -phenylcarbamylamino-S-pyrazolone 1-phenyl-3 -pa1mitylamino-S-pyrazolorie1-phenyl-3-benzenesulfony1amino-5 -pyrazolone 1- (p-phenoxyphenyl) -3-(p-tert. amyloxybenzoyl amino- S-pyrazolone 1- 2,4,6'-tribromophenyl-3-benzamido-5-pyrazolone 1-(2.,4',6'-trichlorophenyl)-3-benzamido-5-pyrazolone 1- (2,4,6'-trichlorophenyl -3-phenylacetamido- 5-pyrazolone 1- 2,4',6'-tribromophenyl) -3-phenylacetamido- 5 -pyrazolone 1- (2,4-dichlorophenyl) -3 [3(2"',4"'-di-tert. amylphenoxyacetamido benzamido] -5-pyrazolone 1-(2',4',6-trichlorophenyl -3- 3-(2"',4'-di-tert.amylphenoxy-acetamido)benzamido1-5-pyrazolone 1-2',4',6'-tr1brornophenyl -3- 3"- 2",4"-di-tert.

amylphenoxy-acetamido )benzamido] -5-pyrazolonel-2,4',6-trichlorophenyl) -3- [3- (2',4"'-di-tert. amylphenoxy)-propionamido] -5-pyrazolone 1- (2',4,6-tribromophenyl) -3- [18-(2',4'-di-te1't. amylphenoxy) -propionamido] -5-pyrazolone 1- (2,5'-dichloro) -3- 3"- (4"-tert. amylphenoxy) benzamido1-S-pyrazolone 1-(2',4,6-tribromophenyl) -3- [3 (4"'-tert. amylphenoXy) benzamido] -5-pyrazolone l-(2',5-dichlorophenyl) -3- [3 2",4"'-di-tert.amylphenoxyacetamido benzamido] -5-pyrazolone COUPLERS PRODUCING YELLOWIMAGES N-amyl-p-benzoylacetaminobenzenesulfonateN-(4-anisoy1acetaminobenzenesulfonyl) -N-benzyl-mtoluidine N-(4-benz0y1acetaminobenzenesulfonyl) -N-benzyl-mtoluidineN-(4-benzoylacetaminobenzenesulfonyl) -N-n-amy1-ptoluidine N-(4-benzoylacetaminobenzenesulionyl -N-benzylaniline w-(p-benzoylbenzoyl) acetanilide w-benzoylacet-2,S-dichloroanilidew-benzoyl-p-sec. amylacetanilide N,N'-di(w-benzoylacetyl-p-phenylenediamine N,N-di- (acetoacetamino) diphenyl oc{ 3- [a-2,4-di-tert.-amylphen0xy) butyramido] benzoyl}-2-methoxyacetanilidea-{3- a- 2,4-di-tert.-amylphenoxy) acetamido]benzoyl}-2-methoxyacetanilide 4,4-diacetoacetamino -3,3-dimethyldiphenyl p,p'-diacetoacetamino) diphenylmethaneethyl-p-benz0ylacetaminobenzenesulfonateNonyl-p-benzoylacetaminobenzenesulfonate N-phenyl-N-(p-acetoacetaminophenyl urea n-propyl-p-benzoylacetaminobenzensulfonateacetoacetpiperidine w-benzoylacetpiperidide N (w-benzoylacetyl 1 ,2,3,4-tetrahydroquinoline N (w-benzoylacetyl) morpholine Photographicemulsions of the invention intended for use in color photography insystems wherein a dye (e.g., dye-bleach process) or the color-formingcomponents are incorporated in the emulsions themselves, it is to beunderstood that these bleachable dyes or color-forming components can beincorporated in the emulsions according to any of the methods well knownto those skilled in the art of photography. Since it is desired that thecolor-forming -components or couplers not wander from the layers inwhich they are incorporated, couplers which do have wandering tendenciescan be employed in a useful manner according to the technique describedin Jelley and Vittum US. Patent 2,322,027, issued June 15, 1943. Thismethod comprises adding the color coupler to a water-immisciblecrystalloidal solvent, such as tr icresyl phosphate or dibutyl phthalateand adding the solution to an aqueous emulsion. Where the couplers arecharacterized by inherent non-wandering characteristics due to thepresence in the coupler molecules of a fatty type radical (e.g.,l-(2,4,6-trichlorophenyl)-3-n-pentadecyl-5- pyrazolone; 1 phenyl 3n-pentadecyl-4-(l-phenyl-S- tetrazolylthio) 5 pyrazolone;1-phenyl-3-(3,5-disulfobenzamido) 4(2-hydroXy-4-n-pentadecylphenylazo)-5- pyrazolone dipotassium salt,etc.), the coupler can be incorporated in the emulsion simply bydissolving it in a convenient organic solvent which does not have anydeleterious effect upon the emulsion. Of course, the nature of thesolvent will vary depending upon the solubility characteristics of theparticular coupler. In general, solvents, such as pyridine,triethanolamine, ethyl alcohol, etc., can be employed for this purpose.

When used in the preparation of photographic systerns such as silverhalide systems intended for color photography, such systems can beoptically sensitized with cyanine and merocyanine dyes, such as thosedescribed in Brooker U.S. Patents 1,846,301, issued February 23, 1932;1,846,302, issued February 23, 1932, and. 1,942,854, issued January 9,1934; White U.S. Patent 1,990,507, issued February 12, 1935; Brooker andWhite U.S. Patents 2,112,140, issued March 22, 1938; 2,165,338, issuedJuly 11, 1939; 2,493,747, issued January 10, 1950, and 2,739,964, issuedMarch 27, 1956; Brooker and Keyes U.S. Patent 2,493,748, issued January10, 1950; Sprague U.S. Patents 2,503,776, issued April 11, 1950, and2,519,001, issued August 15, 1950; Heseltine and Brooker U.S. Patent2,666,761, issued January 19, 1954; Heseltine U.S. Patent 2,734,900,issued February 14, 1956; Van Lare U.S. Patent 2,739,149, issued March20, 1956; and Kodak Limited British Patent 450,958, accepted July 15,1936.

The present photographic systems intended can also be used in diffusiontransfer processes which, for example, utilize undeveloped silver halidein non-image areas of the negative to form a positive by dissolving theundeveloped silver halide and precipitating it on a receiving layer inclose proximity to the original silver halide emulsion layer. Suchprocesses are described in Rott U.S. Patent 2,352,014, issued June 20,1944, and Land U.S. Patents 2,584,029, issued January 29, 1952;2,698,236, issued December 28, 1954; 2,543,181, issued February 27,1951, and 2,698,245, issued December 28, 1954; and Yackel et al. U.S.Patent 3,020,155, issued February 6, 1962. My photographic systems canbe advantageously used in diflusion transfer systems utilized fordocument copying, and in those wherein a silver halide emulsion layer iscoated adjacent to a fogged silver halide emulsion layer or a layercontaining silver precipitating nuclei, such as nickel sulfide. Thesensitive emulsion, following development, is then washed off, leavingthe positive image in the light-insensitive layer containing thediffused silver image.

The present photographic systems can also be used in color transferprocesses which utilize the diffusion transfer of an imagewisedistribution of developer, coupler or dye, from a light-sensitive layerto a second layer, while the two layers are in close proximity to oneanother. Color processes of this type are described in Land U.S. Patents2,559,643, issued July 10, 1951, and 2,698,798, issued January 4, 1955;Land and Rogers Belgian Patents 554,933 and 554,934, granted August 12,1957; International Polaroid Belgian Patents 554,212, granted July 16,1957, and 554,935, granted August 12, 1957; Yutzy U.S. Patent 2,756,142,granted July 24, 1956, and Whitmore and Mader Canadian Patent 602,607,issued August 30, 1960. The sensitizing combinations are compatible witha wide variety of dye-developer combinations, including anthraquinonedye developers, such as 4-[1,5'- bis (2",5"-dihydroxyphenyl) 3' pentyl]amino 1- hydroxyanthraquinone, or azo dye developers, such as 2,4 bis(2,5 dimethoxy 3' [2"-(2",5-dihydroxy- 4 methylbenzoyl)isopropyl]phenylazo) 1 naphthol. Such dye developers can be incorporated in thelightsensitive emulsions themselves, or they can be incorporated in ahydrophilic colloid (e.g., gelatin) layer located contiguous to thenoble metal-selenium sensitized lightsensitive emulsion.

The present photographic systems can be used in the preparation ofphotographic products wherein a photographic developing agent isincorporated in a light-sensitive emulsion, or in a hydrophilic colloidlayer contiguous with the emulsion, for example, in photographicproducts of the type described in Yutzy et al. U.S. Patent 2,725,298,issued November 29, 1955, or in Yutzy et al. U.S. Patent 2,739,890,issued March 27, 1956. The novel photographic systems of my inventioncan be used in the production of photographic products containing, forexample, at least about 5 grams per mole of silver halide of adeveloping agent, such as 1-phenyl-3-pyrazolidone and wherein theemulsion is coated on a fibrous support which contains sufiicientmoisture so that upon heating the exposed element, a negative silverimage is obtained directly without the application of liquids. Such aproduct is described in Stewart et al. U.S. application Serial No.221,031, filed September 4, 1962. This is not to say that the emulsionsof my invention cannot be used in liquid systems which may or may notuse a wide variety of processing solutions or viscous liquids, includingsystems which use pod processing. They can also be used in thepreparation of photographic materials which are designed to be processedin non-aqueous systems or in systems designed to be processed by theapplication of steam.

The novel photographic systems of the invention can also be used inmonobath processes such as are described in Haist et al. U.S. Patent2,875,048, issued February 24, 1959, and in web-type processes, such asthe one described in Tregillus et al. U.S. patent application Serial-No. 835,473, filed August 24, 1959, now U.S. Patent No. 3,179,517.

Also, the novel photographic systems of the invention can be used in thepreparation of lithographic printing plates using, for example,techniques as described in Kodak French Patent 1,280,832, issuedNovember 27, 1961.

It has been found that the photographic systems of my invention cancontain, in addition to labile sulfur compounds, certain stabilizers orantifoggants that are particularly useful for reducing incubation fog.Useful stabilizing compounds for the emulsions of my invention includethe salts of noble metals, especially palladium and platinum, includingsuch salts as are described in Trivelli and Smith U.S. Patents2,566,245, issued August 28, 1951, and 2,566,263, issued August 28,1951. 7 Another group of stabilizers which are quite useful in myinvention comprise the alkane-, areneand heterocyclic sulfinic acids andtheir water-soluble salts (sodium benzene sulfinate, methane sulfinicacid, ethane disulfinic acid, etc., includ ing stabilizers disclosed inBrunken U.S. Patent 2,057,764, issued October 20, 1936). Another groupof useful stabilizing compounds include urazole stabilizers, such asurazole, l-phenyl dithiourazole, l-ethyl dithiourazole, etc., includingstabilizers disclosed in Howe U.S. Patent 2,538,599, issued December 19,1950. Other useful stabilizers include mercury compounds such as thosedisclosed in Allen et al. U.S. Patent 2,728,663, issued December 27,1955; Carroll et al. U.S. Patent 2,728,664, issued December 27, 1955 andLeubner et al. U.S. Patent 2,728,665, issued December 27, 1955. It hasalso been found that the photographic systems of the invention can befurther stabilized with disulfide compounds, including the cyclicdisulfides of Kodak Belgian Patent 569,317, or the aliphatic disulfidesof Herz and Kalenda U.S. Patent 3,043,696, issued July 10, 1962. Anothergroup of disulfide stabilizing compounds which have useful effects in myinvention include those containing a carbamylalkyl radical, wherein thecarbamyl radical is aliphatic or cycloaliphatic (e.g., where thenitrogen atom of the carbamyl radical forms a part of a heterocyclicring, such as pipen'dyl, morpholinyl, etc., as in the case of bis-(N-morpholinylcarbonyloxyethyl)-disulfide). Also useful in stabilizing theemulsions of my invention is Nitron and similarly constitutedtetrazoles, particularly Nitron in combination with a salicylic acidsuch as 5-(1,1,3,3-tetramethylbutyl)salicylic acid.1-phenyl-5-mercaptotetrazoles are useful stabilizers in the invention.Water-soluble salts of Group H elements of the Periodic Table such asmagnesium, calcium, strontium, barium, cadmium and zinc, organictertiary phosphines and azaindenes such as triazaindenes, tetrazaindenesand pentazaindenes are also useful stabilizers in the photographicsystems of the invention. Typical suitable azaindenes are disclosed inHeimbach and Kelly U.S. Patents 2,444,605 and 2,444,606, issued July 6,1948; Heimbach U.S. Patents 2,444,607, issued July 6, 1948, and2,450,397, issued September 28, 1948; Heimbach and Clark U.S. Patent2,444,609, issued July 6, 1948; Allen and Reynolds U.S. Patents2,713,541, issued July 19, 1955, and 2,743,181, issued April 24, 1956;Carroll and Beach 13 U.S. Patent 2,716,062, issued August 23, 1955;Allen and Beilfuss U.S. Patent 2,735,769, issued February 21, 1956;Reynolds and Sagal U.S. Patent 2,756,147, issued July 24, 1956; Allenand Sagura U.S. Patent 2,772,164, issued November 27, 1956 and Z. Wiss.Phot., vol. 47, 1952, pages 2 to 28.

A particularly useful class of stabilizers or antifoggants that can beutilized to control fog in the photographic systems of the invention arethe derivatives of hydroxy carboxylic acids described in the copendingapplication of Humphlett, U.S. Serial No. 413,962, filed November 25,1964, and which stabilizer addenda can be represented by the followingFormulas A and B:

A. O I! ($11M)... o l (drum and wherein: M and Z are each hydroxyradicals or acyloxy radicals wherein R is an alkyl radical or an arylradical); X is a hydrogen atom, an acyloxymethyl radical if (-CHgOCRwherein R is an alkyl radical or an aryl radical) or a carbinol radical(CH OH); Y is a carboxy radical II (-0 OH) 21 carbamyl radical II N112)or a radical having the formula II COR wherein R is an alkyl radical(more generally having 1 to 2 carbons, particularly when Z is a hydroxylradical); A is a carbinol radical, a radical having the formula asdescribed for Y, a carboxy radical, an acyloxymethyl radical or acarbamyl radical; m is an integer of 2 to 3; n is an integer of 1 to 5;and 0 is an integer of O to 2. The subject addenda contain at least onecarbamyl or ester moietyincluding a or 6 lactone or inner ester groups(e.g., Formula A) as Well as the more conventional ester groupsdescribed above ii i (e.g., -ocr -oon Hence, at least one of A, Yand Zof Formula B forms a carbamyl or an ester radical. Typical usefulantifoggant 'addenda can be represented by the following more subgenericformulas:

wherein: R is an alkyl radical having 1 to 2 carbon atoms; R and R areeach an alkyl radical which more generally has 1 to 8 carbon atoms or aphenyl radical, including substituted phenyl radicals; R is an alkylradical which more generally has 1 to 8 carbon atoms or a hydrogen atom;p is an integer of 2 to 3; and q is an integer of 1 to 5. Othersubgeneric formulas defining antifoggant addenda of the inventionincluded within generic Formulas A and B can be formulated. The alkylsubstituents described above suitably have 1 to 20 carbon atoms, andpreferably 1 to 8 carbon atoms, including methyl, ethyl, isopropyl,butyl, heptyl, octyl, decyl, octadecyl, eicosyl and the like. The arylsubstituents described above include such radicals as phenyl, tolyl,naphthyl and the like, phenyl being preferred.

The above-described stabilizers or antifoggants can be utilized inconventional antifoggant amounts, the amount utilized varying with theparticular stabilizer and the elfect desired in accordance with usualpractice. Mixtures or combinations of more than one of theabove-described stabilizers can be utilized. Such stabilizers, e.g., theazaindenes and mercury salts, which are normally added just prior tocoating can, if desired, be included during the chemical sensitizationof the silver halide emulsion.

The photographic systems stabilized with a labile sulfur compound inaccordance with the invention can be any photographic system that issensitized with noble metals and labile selenium. The invention thus hasutility, not only for silver halide photographic systems, but also, forother light-sensitive systems such as other light-sensitive silversalts, thallous halides, cuprous halides, lead halides and relatedlight-sensitive heavy metal salts.

The following examples will serve to illustrate the useful stabilizingeffects obtained in my invention when combinations of noble metalsensitizers and selenium sensitizers are employed.

Example 1 dimethylselenourea (a labile selenium compound) and 4.0

mg. per mole of potassium chloroaurate, this emulsion being furthermodified by the addition of mg. per mole of sodium thiocyanate (CoatingB). The third portion of emulsion was sensitized exactly as in the caseof the second portion of emulsion, except that 8.0 mg. per mole ofsodium thiosulfate (a labile sulfur compound) were added (Coating C).Each of the portions of emulsion was then coated on a cellulose acetatefilm support 15 and dried, the coating samples being designated A, B andC, respectively, in Table I. The samples were then exposed in the usualmanner on an Eastman Ib sensitometer and developed for minutes at 72 F.,fixed in hypo,

of 540 mg, of silver and 400 mg. of gelatin per square foot. A sample ofeach coating was exposed in an Eastman Ib sensitometer, developed for 8minutes at 72 F., fixed in hypo, washed and dried in the usual manner.

washed and dried in the usual manner. The developing 5 The developingcomposition utilized had the following composition utilized is set outbelow: composition:

Grams Grams gI n.1ethyl-p ammop henol Sulfate u N-methyl-p-aminophenolsulfate 2.0 odiumsulfite (anhydrous) 30.0 S lfit h d 90 O Hydroquinone2.5 10 0 mm e an y mus S Hydroqumone 8,0

0 rum metaborate octahydrate 10.0 Potassium bromide u 05 Sodiumcarbonate monohydrate 52.5 Water to make 1.0 liter. Potassium bmmldeWater to make 1.0 liter. The results are summarized in the data set outin Table I. TABLE In TABLE I Coating Sulfur Compound Relative 'y FogRela- Speed Coating Feature Addenda (mg/Ag mole) tive Fog speed (A).None 100 3.26 0.23 0 (B) Sodium thiosull'ate 100 3.48 0.15 Sulfur(1G.0)+gold (4.0) 100 .08 Selenium (3.2)+g0ld (4.0).. 132 .20

Sulfur (8.0)+gold (4.0)|selemum (1.6) 141 07 Exampl 4 As illustrated bythe data set out in Table I, the labile A fi e- Siivei' gelatin)Fhioiobromide emuisiofl ulf Compound fi ti ly controlled h f h fogcontaining 60 mole percent bromide was chemically sensior sensitizingfog of the selenium-gold sensitized emuliiZeCi y adding, p mole ofSiiVei' e b of P sion. Similar results were obtained when a fine-grainediasslilm ChiOTO'fmIeTe, 50 of Sodium Y gelatino silver chlorobromide (60mole percent bromide) gof N,N'd1meii{Yi5eieI10ufea,. and 2 gof Sodlllmemulsion was treated with a labile sulfur compound (e.g., iiilosilifaief heeilng for 10 minutes at C" the P 10 g. of sodium thiosulfate) inaddition to being selenium 0f the emuisloi} being at fiuiiilg epe i ofsand gold sensitized as dgscribed above A second portion was chemicallysensitized 1n the same manner but with the addition of 220 mg. of4-hydroxy-6- Example 2 methyl-1,3,3a,7-tetraazaindene per mole of silverhalide A moderately coarse-grained, gelatino silver bromoand heated forthe same time, at the same temperature iodide emulsion containing 3.24mole percent iodide was and p The Chemically sensitized emulsions wereeach chemically sensitized by adding, per mole of silver halide, coatedon cellulose acetate film supports at coverages of 2 mg. of potassiumchloroaurate, 100 mg. of sodium thio- 540 mg. of silver and 400 mg. ofgelatin per square foot. cyanate, and 0.8 mg. of N,N-dimethylselenoureaand heat- A sample of each coating was exposed on an Eastman ing for 30minutes at 60 C. (Coating A). Other por- Ib sensitometer and processedas described in Example 3. tions (Coatings B and C), were chemicallysensitized in TABLE IV the same manner but with the addition of a labilesulfur compound as shown in Table II and heated at the time CoatingAmount of Azamdene Relative 7 Fog and temperature shown in Table II. Thechemically sen- Speed sitized emulsions were each coated on a celluloseacetate support at coverages of 540 mg. of silver and 500 mg. of (A)-Nnne 100 5,30 0,14 gelatin per square foot. A sample of each coating was(B) 220 mg'hmie sliver 100 exposed on an Eastman lb sensitometer andprocessed as described in Example 1. Similar results are obtained ifmercury salts are substi- TABLE II Ctg. Sulfur Compound (mg/mole) Time.Temp. of Relative 'y Fog Heat Treatment Speed (A) None 100 3.06 0. 26(13).--- Diacetylthiuurea (1 mg.) 100 3. 34 0.12 (0)...-Isopropylthiocarbamate (2 mg.) 95 3.50 0.09

Similar results as those described in Table II are obtained tuted forthe tetraazaindene as antifoggants (e.g., 1 mg. it 0.8 mg. of colloidalselenium per mole of silver halide of mercuric chloride per mole ofsilver halide). Mixtures were substituted for the N,N-dimethylselenoureaas the 0 of such azaindenes and mercury salts are also useful antilabile selenium addendum. foggant combinations. Likewise, 300 mg. of5carbeth- Example 3 oxy-2,6-dirnethyl-4-thiopyrimidine per mole ofsilver halide substituted for the tetraazaindene further reduced Amoderately fine-grained, gelatino silver bromoiodide the fog level.emulsion containing 5.2 mole percent iodide was chemi- Example 5 callysensitized by adding, per mole of silver halide, 3 mg. of potassiumchloroaurate, 100 mg. of sodium thiocyanate, A fi i gelatin) f fbromolodldf i and 24 of NN dimethylselenourea and heating for containing4.2 mole percent iodide was chemically sensi- 10 minutes at c. (CoatingA). A second portion was e by addmg, P mole 0f Sliver f 2 0f chemicallysensitized by adding, per mole of silver halide, 70 tasslumchloroaurate, 100 of Sodium thiocyanaie, 4 mg. of potassiumchloroaurate, 100 mg. of sodium thioof N,Ndimethyiseienourea, and 4 mgof Sodium t 34 mg of N,Ndimethylselenourea and 4 thiosulfate and heatingfor 10 minutes at 65 C. (Coatof sodium thiosulfate and heating 12minutes at 60 C. ing A Second Portion Was Chemically sensitized in(Coating B). The chemically sensitized emulsion was the Same manner butwith the addition of 267 mg. 4- coated on a cellulose acetate filmsupport at a coverage hydroxy-6-methyl-1,3,3a,7-tetraazaindene per moleof TABLE V Coating Amount of Tetraazaindene Relative 7 Speed Fog Similarresults as those set out in Table V were obtained when 400 mg. of-acetamido-4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene per mole ofsilver halide or 400 mg. of 2 methyl-mercapto 4hydroxy-6-methyl-l,3,3a,7-tetraazaindene per mole of silver weresubstituted for the 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene. Suchtetraazaindenes also substantially reduced the fog level of the coatingsthat were incubated for one week at 120 F. and 50% RH.

Example 6 A moderately coarsegrained gelatino silver bromoiodideemulsion containing 3.24 mole percent iodide was chemically sensitizedby adding, per mole of silver halide, 2 mg. of potassium chloroaurate,100 mg. of sodium thiocyanate, and 4 mg. of tri-p-tolylselenophosphateand heating for 15 minutes at 65 C. (Coating A). A second portion waschemically sensitized in the same manner, but with the addition of 2 mg.sodium thiosulfate and heated for the same time at 65 C. (Coating B).The chemically sensitized emulsions were coated on cellulose acetatefi-lm supports. A sample of each coating was exposed on an Eastman Ibsensitometer and processed as described in Example 1.

TABLE VI Coating Relative 'y Fog Sulfur Compound Speed None- Sodiumthiosul fate The -tri-p-tolylselenophosphate used in this example wasprepared by the method described by Heiks and Croxton in Industrial andEngineering Chemistry, vol. 43 (1951), page 876. Such selenium compoundscan be called selenophosphates and can be represented by the followinggeneral formula:

wherein R represents an alkyl radical, such as butyl, isopropyl, amyl,isoamyl, etc., or an aromatic radical, such as phenyl, tolyl (o, m orp), etc. Such selenium compounds can be used as labile seleniumcompounds in sensitizing the emulsions of the invention.

Example 7 'A moderately coarse-grained gelatino silver bromo iodideemulsion containing 3.24 mole percent iodide was chemically sensitizedby adding, per mole of silver halide, 2 mg. of potassium chloroaurate,100 mg. of sodium thiocyanate, and 2.6 mg. of selenobenzophenone andheating for 20 minutes at C. (Coating A). Other portions were chemicallysensitized in the same manner, but with the addition of sodiumthiosulfate in the amounts shown below, and heated at 65 C. for thelength of time shown in Table VII (Coatings B and C). The chemicallysensitized emulsions were then coated on cellulose acetate filrnsupports. A sample of each coating was exposed on an Eastman Ibsensitometer and processed as described in Example 1.

To one mole of a gelatino silver bromoiodide (94 mole percent bromide, 6mole percent iodide) photographic emulsion was added 2 mg. potassiumchloroaurate, 2 mg. sodium thiosulfate pentahydrate, 100 mg. sodiumthiocyanate and 1.6 mg. N,N-dimethylselenourea. The emulsion was thendigested at 60 C. to obtain optimum sensitivity. The emulsion was thendivided into several portions to which were added the concentrations ofthe addenda listed in Table VIII below. The emulsions were then coatedon a film support to yield a silver coverage of 540 mg. per square footand a gelatin coverage of 500 mg. per square foot. Samples of fresh andincubated coatings were exposed in an Eastman Ib sensitometer andprocessed as described in Example 1 to yield the following results:

TABLE VIII Fresh One Week Inc.

120F.50%R.H. Feature Addenda (gJAg mole) Rel. 1 Fog Rel. 1 Fog SpeedSpeed Control 100 2. 64 0. 16 120 1. 42 1. 94 Control plus Compound II(10.0). 100 2. 64 0. 12 95 2. 20 0. 98 Control plus Compound II (20.0)105 2. 64 0. 12 100 2. 42 0. Cont ol plus Compound III (20 0) 91 2. 660.12 69 1. 93 1. 30 Control plus Compound IV (10.0) 100 2.70 0.16 120 1.86 1.38 Control plus Compound 1 (2.0) 100 3.00 0.07 138 2.80 0.17Control plus Compound I (2.0) plus Compound II (10.0) 100 2. 84 0. 06115 2. 70 0. 13 Control plus Compound I (2.0) plus Com- 0) plus CompoundIII (20.0) 2. 94 0. 06 2. 50 0. 11 Control plus Compound I (2.0. plusCompound IV (10.0) 105 2. 80 0. 08 120 2. 50 0. 24 Control plus CompoundI (2.0) plus Cornpound IV (20.0) 2.82 0. O6 2. 62 0.18

19 In the above table, Compound I is 4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene, Compound H is methyl-L-arabonate, Compound III isD-arabonamide and Compound IV is 'glucono-y-lactone. Other relatedhydroxy carboxylic acid derivates that can also be suitably utilized asantifoggants in the described gelatino silver bromoiodide emulsion atconcentrations of 20 grams per mole of silver halide, or in combinationwith 2 grams per mole of silver halide of4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene, include: diethyl mucate,methyl D-arabonate, ethyl D-ara-bonate, methyl L-arabonate tetraacetate,D-arabono- -lactone, isopropyl L-arabonate, isobutyl D-arabonatetetraacetate, methyl (tetraacetyl-D-arabonyl)glycolate, D gluco-D-guloheptone- -lactone, D gl-uco-D-gulo heptonoamide, methylD,L-glycerate, dimethyl D-tartrate, D-glucono-filactone, D-gluco-namide,D-gluco-D-guloheptonic acid hexaacetate monohydrate, D-galactonic acidpentaacetate, D-arabono-y-lactone, D-galactonamide, D-lyxono-y-lactone,D-mannonamide, and the like. Such hydroxy carboxylic acid derivativescan be utilized in a wide range of autifoggant concentrations, althoughconcentrations of about 5 to 100 grams per mole of silver halide aregenerally utilized.

Example 9 A coating of vacuum deposited silver bromide is made on acellulose acetate film support and overcoated with a thin layer ofgelatin by the method described in Example 1 of copending Rasch et al.application U.S. Serial No. 415,596, filed December 3, 1964. Theresulting photographic element is immersed for five minutes at 68 F. inthe following sensitizing solution:

Mg. Sodium thiosulfate 4.00 Potassium chloroaurate 4.00N,N-dimethylselenourea 0.25 Water to make 200.00 ml.

(pAg adjusted to 8.5 with aqueous potassium bromide.)

The resulting treated photographic element is then allowed to air dry inthe dark at 68 F. The resulting dried photographic element is thenexposed to roomlight for 10 seconds through a neutral density stepwedgeand developed for 10 seconds in Kodak D-72 developing solution, fixed inhypo, washed and dried in the usual manner. The fog level of theresulting processed photographic element is low when compared to asimilarly exposed and processed photographic element prepared in thesame manner except that the sodium thiosulfate is omitted from thesensitizing solution.

Example 10 To a fine-grained gelatino silver chlorobromide emulsioncontaining 60 mole percent bromide and 40 mole percent chloride wasadded 4.4 mg. of potassium chloroaurate, 50 mg. of sodium thiocyanate,2.2 mg. of N,N- dimethylselenourea, and 2 mg. of sodium thiosulfate, andthe emulsion heated at about 60 C. for about minutes. Thereafter toseparate portions of the emulsion were added the antifoggants listed inTable IX below and the emulsions were coated on cellulose acetate filmsupports at coverages of 137 mg. of silver and 202 mg. of gelatin persquare foot. Samples of the films were exposed in an Eastman lbsensitometer, both before and after an incubation period and processedas described in Example 3. The data set out in Table IX illustrates thatS-mercaptotetrazoles can be utilized in emulsions of the invention toreduce incubation fog.

2% TABLE 1X Fresh One Week Ine.,

120 F. Compound MgJAg mole Rel. y Fog Rel. 7 Fog Speed Speed NoneControl 100 1. 96 0.10 91 0.78 (A). "2-- 500 91 1.88 0.06 120 1.75 0.27

B 94 1. 86 0. 18 1%0 Control 1. 96 0. 1 7 2" 90 94 2. 08 0.07 91 1.63 0.24

The compounds of Table IX are identified as follows:

(A) :1- 3-acetamidophenyl) -5- mercaptotetraz0le (B):1-(3,5-dicarboxyphenyl)-o-mercaptotetrazole (C) :1-o-curhomethoxyphenyl) -5-mercaptotetrazole Example 11 A moderatelycoarse-grained, gelatino thallous bromoiodide emulsion containing 13mole percent iodide and 87 mole percent bromide is chemically sensitizedby adding, per mole of thallous halide, 10 mg. of potassiumchloroaurate, 40 mg. of seleno-DL-cystine and 10 mg. of sodiumthiosulfate, and thereafter heating for 10 minutes at 40 C., thencooling to 35 C. The chemically sensitized emulsion is coated on acellulose acetate film support at a coverage of 306 mg. of thallium and450 mg. of gelatin per square foot. A sample of coating is hardened bybathing 5 minutes in a 3 percent solution of potassium chrome alum,washed, and dried. The sample is exposed through a step tablet for 5minutes with a SOO-watt photoflood lamp at a distance of 9 inches. Theexposed sample is processed at 68 F. by bathing 5 minutes in a 10percent silver nitrate solution, washing 1 minute in distilled water,bathing 5 minutes in a 2 percent potassium bromide solution, washing 1minute in distilled water, developing 4 minutes in the developerdescribed in Example 3, followed by the usual fixing in hypo, washing,and drying. A similar coating of an emulsion prepared in the absence ofthe labile sulfur compound, sodium thiosulfate, during the chemicalsensitization has a substantially higher fresh fog level when exposedand processed as described above. The preparation of thallous bromideand thallous bromoiodide emulsions is described in papers by J. A. Thom,Sci. et Ind. Phot. (2), 18, 193-204 (1946); N. Ritchie and J. A. Thom,Trans. Far. Soc. 42, 418 (1946); and E. Brauer and H. J. Wehran, Phot.Korr. 93, 67 (1957). Chemical sensitizations of thallous bromoiodideemulsions by rhodium chloride, gold chloride, sodium thiosulfate,cystine, and active gelatins (alone or in combination) are described inpapers by E. Brauer, Phot. Korr. 94, 35 (1958), E. Brauer, Phot. Korr.,93, 67 (1957), and E. Brauer, Sci. et Ind. Phot. (2), 29, 161 (1958).

Example 12 In a manner similar to that described in Table G, column 25of US. Patent 3,046,129, issued July 24, 1962, a conventionalphotographic gelatino silver bromoiodide emulsion was divided into threealiquot portions, each portion containing a conventional magentacoupler, such as one of those identified in Fierke et al. US. Patent2,801,171 (e.g., coupler No. 7). A sample of the emulsion is sensitizedto its optimum sensitivity with aurous thiosulfate at 3.3 mg. per moleof silver halide and dimethylselenourea at 0.2 mg. per mole of silverhalide, the emulsion containing sodium thiosulfate at 2 mg. per mole ofsilver halide during the sensitization. The emulsion is coated on acellulose acetate film support and dried. The film sample is thenexposed to daylight quality illumination in an Eastman Ib sensitometerand given a conventional negative development in the developingcomposition as described in Example 1. The coating is then flashed towhite light and developed once again in an alkaline color developingcomposition con- 21 taining 4=amino-N,N-diethyl-3-methylanilinehydrochloride as the active developing agent. The metallic silver isthen removed by successive treatments with a ferricyanide bleach bathand fixing bath, followed by water washing in the usual manner. Areversal magenta image is obtained.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinaoove and as defined in the appendedclaims.

Iclaim:

1. In a photographic system sensitized with a noble metal and labileselenium, the improvement which comprises utilizing a labile sulfurcompound as a stabilizer.

In a photographic system sensitized with gold and labile selenium, theimprovement which comprises utilizing a labile sulfur compound as astabilizer.

3. In a silver halide system sensitized with gold and labile selenium,the improvement which comprises utilizing a labile sulfur compound as astabilizer.

4. A photographic silver halide emulsion sensitized with at least twodifferent sensitizers,'one of said sensitizers being a noble metalsensitizer and the other being a labile selenium sensitizer, said silverhalide emulsion being stabilized by the addition thereto of a labilesulfur compound.

5. A photographic silver halide emulsion sensitized with at least twodifferent sensitizers, one of said sensitizers being a gold salt and theother being a labile selenium sensitizer, said silver halide emulsionbeing stabilized by the addition thereto of a labile sulfur compound.

6. A photographic silver halide emulsion sensitized with a gold salt andan organic selenium compound containing divalent selenium doubly bondedto a carbon atom of said compound through a covalent linkage, saidsilver halide emulsion being stabilized by the addition thereto of alabile sulfur compound.

7. A photographic silver halide emulsion sensitized With a gold salt anda labile selenium sensitizer, said silver halide emulsion beingstabilized by the addition thereto of a labile sulfur compound and atetraazaindene antifoggant.

8. A photographic silver halide emulsion sensitized with a gold salt anda labile selenium sensitizer, said silver halide emulsion beingstabilized by the addition thereto of a labile sulfur compound and amercury compound antifoggant.

9. A photographic gelatino silver halide emulsion sensitized with a goldsalt and a labile selenium sensitizer, and containing a labile sulfurcompound as a stabilizer.

10. A photographic silver halide emulsion as described in claim 4wherein the labile selenium sensitizer is a selenourea.

11. A photographic silver halide emulsion as described in claim 4wherein the labile selenium sensitizer is a selenophosphate.

12. A photographic silver halide emulsion as described in claim 4wherein the labile sulfur compound is a thiosulfate.

13. A photographic silver halide emulsion as described in claim 4wherein the emulsion contains a color-forming photographic coupler.

14. A photographic silver halide emulsion as described in claim 4,sensitized in the presence of a watersoluble thiocyanate.

15. A photographic silver halide emulsion as described in claim 5wherein the labile selenium sensitizer is N,N-dimethylselenourea.

16. A photographic silver halide emulsion as described in claim 5wherein the labile sulfur compound is sodium thiosulfate.

22 17. A photographic silver halide emulsion as described in claim 5wherein the labile sulfur compound is u G i (outing, o and (UHZ)n H (nmoX wherein:

(l) M and Z are each selected from the group consisting of a hydroxyradical and an acyloxy radical having the formula i o CR wherein R isselected from the group consisting of 12.11 alkyl radical and an arylradical;

(2) X is selected from the group consisting of a hydrogen atom, acarbinol radical, a radical having the formula II -OH2OCR wherein R isselected from the group consisting of an alkyl radical and an arylnadical;

(3) Y is selected from the group consisting of a carboxy radical, acarbamyl radical and a radical having the formula ll GOR1 wherein R isan alkyl radical;

(4) A is selected from the group consisting of a carbinol radical, acarbamyl radical, a carboxy radical, a radical having the formula u OORwherein R is an alkyl radical and a radical having the formula i oHzohRwherein R is selected from the group consisting of an alkyl nadical andan aryl radical;

(5) m is an integer of 2 to 3;

(6) n is an integer of 1 to 5; and

(7) o is an integer of 0 to 2; except that at least one of A, Y and Zforms a radical selected from the group consisting of a carbamyl radicaland an ester radical.

22. A photographic silver halide emulsion as described in claim 5wherein the labile selenium sensitizer is colloidal selenium.

No references cited.

NORMAN G. TORCHIN, Primary Examiner.

J. RAUBITSCHEK, Assistant Examiner.

1. IN A PHOTOGRAPHIC SYSTEM SENSITIZED WITH A NOBLE METAL AND LABILE SELENIUM, THE IMPROVEMENT WHICH COMPRISES UTILIZING A LABILR SULFUR COMPOUND AS A STABILIZER. 